Keying DV Footage

[mediasaurus]

I've come across some DV footage that needs to be keyed. I can key it great in After Effects with Keylight (thanks in part to the screen pre-blur feature). I'd prefer to use Shake, but have run into a problem. Keylight in Shake, to the best of my knowledge, doesn't have a pre-blur function.

I've tried blurring the blue channel of the source footage before feeding it into Keylight, but then there's a rectangle around the border after it comes out the Keylight node (or Primatte), I guess as a result of black being brought into the edges from the blur and not getting keyed out. I know I can rotoshape this out, but when the subject is along the border, they partially disappear.

Alternatively, I've fed the footage straight into Keylight, edge detected the resulting alpha channel and used that as a mask for a blur. This works okay, but doesn't look as nice as pre blurring the blue channel.

So I'm in a predicament: gray rectangle or sub par alpha channel.

Is there something I might be missing that would let me pre-blur the image before keying without the rectangular ring? Thanks!

[slimbox]

Try this, you can use the Photron Primatte keyer and create an animated garbage matte for the subject when he is near the border.

[user_deleted]

I think he's talking about borders around his character, due to DV compression. Try looking in the macros section, you'll find some to "restore" the compression of your footage. If that doesn't do the trick, you can try to look at each channel (RGB) and try to get a luminance key from one of them (or an operation between them, if that gives you more contrast between the shape and the background). You can also try pulling parts of the key with a lookup node (or a color corrector of your choice) applied to only one channel.
Just experiment a little with these things or any other creative solution, since keying DV footage can be quite tricky.

Good luck!

[frosty3d]

look in the user guide... change colourspace, blur the green chanel and change colour back, or something like that.

[pangea1uk]

Since DV compression scheme subsamples chroma (color difference components) at 4:1 compared to luma (meaning there is 4 times less color information then luma) you need to slightly blur only those channels. Grab a ColorSpace node, change the color space to YUV, attach a blur node and blur only U and V components (change 'rgba' to 'gb' in the blur node), attach another ColorSpace node and convert that to RGB again, then key. Adjust the amount of blur to taste.

Cheers, I.

[user_deleted]

I would try the 4.x.x enhancer macro. You can find it in the Keying section.